Major companies are planning to raise salaries of top executives an average of 11 percent in 1982, according to data gathered by Sibson &amp; Co. Inc., a compensation consulting firm in Princeton, N.J. White-collar employees below the group-vice-president level are slated to get salary increases of 9.9 percent.

Raises for top officers and other workers ''usually have been closer together ,'' says W. Donald Gough, Sibson's managing principal. The 1 percent differential forecast for 1982 ''is an indication of the fact actual increases (for top management) have been running higher.''

While corporate chieftains will have the fastest-rising pay next year, the biggest percentage gains in benefits have recently been won by employees with modest salaries.

For workers with salaries of $10,000, benefits as a percentage of salary climbed to 53.9 percent in 1981, up 4.2 percent from 1980, according to a survey made by Hay-Huggins, a member of the Hay Group. The compensation consulting firm contacted 727 US industrial, financial, and service organizations.

The next largest increase in benefit costs was posted by managers with salaries of $30,000. Their benefits cost the typical company 38 percent of salary in 1980 and 40.6 percent of salary in 1981.

The benefit package for all employees has been getting more costly for a variety of reasons. Major cost increases have come as companies footed bigger tabs for social security payments, health insurance, and cost-of-living adjustments for workers on pensions. Benefit costs are also climbing as employers offer more generous fringes.

The trend toward fatter fringes may moderate during the recession, however, as companies look for ways to cut costs. ''We are getting more interest in cost containment than we have in the past five years,'' says Robert Ochsner, a partner at Hay-Huggins.

Still, the typical employee is finishing 1981 with a better fringe benefit package than ever before. A Hay-Huggins survey completed in May and just released found continued liberalization in a number of benefit areas, including:

* Holidays. More workers now have the option of taking one day off at a time of their choosing. Some 48 percent of the companies Hay- Huggins surveyed now give a ''personal'' or ''floating'' holiday. Last year, only 42 percent of those surveyed offered such a benefit.

The most liberal holiday schedules go to workers in New England and the Mid-Atlantic states. Some 97 percent of New England companies and 84 percent of Mid-Atlantic companies offer at least 10 holidays and most of them more than 10.

* Vacations. The maximum vacation continues to grow longer. Now 55 percent of the companies surveyed by Hay-Huggins have maximum vacations of five weeks or longer. That is up from 46 percent of the companies in 1980.

And workers have to put in less time to earn vacation. As recently as 1977, only 57 percent of the companies surveyed gave three weeks of vacation to workers with one to five years of service. In 1981, 69 percent of those surveyed offered three weeks of vacation to employees with five years or less of service.

* Health care. Dental insurance is the fastest-growing health-related benefit. Some 69 percent of the companies surveyed now offer a dental plan, up from only 34 percent in 1976. In 80 percent of the dental plans, the company pays all expenses.

Hay-Huggins also reports that most employees are increasing the maximum amount their insurance will pay for health-related claims. Some 78 percent of the plans in the Hay survey have maximum benefits of $250,000 or more.

* Pensions. More companies are partly protecting retired workers' pay from the effects of inflation. Some 58 percent of those surveyed adjust retired workers' checks to offset inflation, as against only 33 percent who made adjustments in 1976.

But retired people are not getting anything close to full protection from inflation. Only 8 percent of the companies that make adjustments have any formal schedule for increasing retirement pay. And the pension adjustments are typically only 2 or 3 percent, far less than the inflation rate.

Employers are reluctant to adjust pensions for inflation because of the high and unpredictable costs of doing so. ''It is as much that the cost is unknown as that it is high,'' Mr. Ochsner says.

Inflation is of less concern for top managers, more of whom are being given supplemental pension benefits. Some 35 percent of the companies in the Sibson survey offer senior managers retirement income in addition to the maximum $125, 000 they can receive from a government-insured pension plan. A $200,000-a-year executive who spent 30 years with a company would get $100,000 in supplemental income from a typical plan.